code: def test_free():
      q = Quantity(ETH, 5)
      free = q.free()
  
      assert isinstance(free, Quantity)
      assert free.size == 5 and free.instrument == ETH
      assert not free.is_locked
  
      q = Quantity(ETH, 5, path_id="fake_id")
      free = q.free()
  
      assert isinstance(free, Quantity)
      assert free.size == 5 and free.instrument == ETH
      assert not free.is_locked
  
imports: import pytest
  import unittest.mock
  from tensortrade.oms.instruments import *
  from tensortrade.core.exceptions import *
label_desc: Use image node_id 24 for calling a global function with example usage: test_free() without return types